Method of and lever pin assembly in pump



' Dec. 16, 1969 R. w. DAVIS 3,483,826

METHOD OF AND LEVER PIN ASSEMBLY IN PUMP Filed Sept. 5, 1967 INVENTORROONEY W. DAWS naw/ ATTORNEY United States Patent 3,483,826 METHOD OFAND LEVER rm ASSEMBLY 1N PUMP Rooney W. Davis, St. Louis, Mo., assignorto ACF Industries, Incorporated, New York, N.Y., a corporation of NewJersey Filed Sept. 5, 1967, Ser. No. 665,591 Int. Cl. F04b 43/02; B23p19/02; B21d 39/00 US. Cl. 103-150 6 Claims ABSTRACT OF THE DISCLOSURE Anautomotive diaphragm type fuel pum having a die cast lever arm body isprovided with a lever pin which is installed in a pin receiving slot andsecured therein by peened over portions of the edge of the slot.

This invention relates to diaphragm type pumps and more particularly toa method of and the assembly of the lever pin in the pump.

Diaphragm type automotive fuel pumps of the general type here involvedare exemplified by the one shown and described in the United StatesPatent No. 2,856,862 granted Oct. 21, 1958 to A. C. Korte. In such apump a cam driven rocker arm or lever arm is mounted on a pivot pinwhich is inserted into a drilled hole transverse the body of the pump.

An object of the present invention is to provide an improved method ofassembly and structure for installing the pivot pin in the pump body.

It is a further object of the invention to provide a more economical andsimplified method for and assembly of a diaphragm type fuel pump.

According to the invention the pump body, which may be of die castmetal, is provided with an aperture for receiving a pump rocker arm inwhich there is formed into the body a transverse groove for receiving alever pin and there is further provided adjacent the edges of the grooveraised portions which are subsequently flattened by compression orpeening to secure the pivot pin and the rocker arm in position.

Further objects, advantages and features will appear from theaccompanying drawing, description and the appended claims in which:

FIGURE 1 is an elevation view of a fuel pump having a portion thereofbroken away;

FIGURE 2 is an elevation view of the mounting portion of the body withrocker arm and pivot pin in place;

FIGURE 3 is an enlarged view of a portion of the mounting face of FIGURE2 but less the rocker arm;

FIGURE 4 is an enlarged cross section taken along the lines 4-4 ofFIGURE 3 and;

FIGURE 5 is a cross section taken along the lines 55 of FIGURE 3 and;

FIGURE 6 shows another embodiment similar to that of FIGURE 4.

Referring to the drawing there is shown generally at 10 in FIGURE 1 apump of the diaphragm type. Pump 10 is Provided with a body 12 having anaperture 14 for receiving a rocker arm 16 as shown. The rocker arm isactuated by a cam 18 mounted on a cam shaft 20 which is driven by theinternal combustion engine.

A pumping chamber 22 surmounts body 12 and includes a suitablediaphragm, springs and inlet and outlet check valves. Further details ofthe pumping chamber is substantially similar to that of the Korte Patent2,856,862 mentioned earlier.

Cam 18 imparts motion to the rocker arm 16 which in turn causes the pumpstem 24 to reciprocate. Stem 24 is provided with a head 26. A cushioningmember 28 is interposed between head 26 and a bifurcated end 30 ofrockice er arm 16. A spring 32 urges rocker arm 16 onto the surface ofcam 18 at all times. Rocker arm 16 is pivoted on a pin 40.

FIGURE 2 shows the mounting end of the fuel pump and illustrates thefinal assembly of the rocker arm pin 40 and the rocker arm 16 in thecavity 14. Pin 40 is recessed below the face 42 of the mounting flange.The recessed portion is shown at 44. Details of the pin mounting and themethod of installation are shown in FIGURES 3, 4 and 5.

For clarity the rocker arm has not been shown in FIGURE 3 but it will beunderstood that the rocker arm would be in place at the time of finalassembly. The righthand portion of FIGURE 3 shows the condition of thepin after final assembly while the lefthand portion shows it during anintermediate step in the assembly operation.

Referring to FIGURES 4 and 5 there is shown a slot 50 which receives thepin. The bottom of slot 50 is provided with rounded corners 52 having aradius only slightly greater than that of the pin itself. A lip or bead54 traverses the length of each of the slots. Slot 50 may have a slightdraft as for example approximately 1 degree. Since the entire bodyportion 12 is conveniently formed by die casting of a suitable metalsuch as aluminum, zinc or magnesium, the draft just mentioned is of someassistance in the die casting operation. Pin 40 is press-fit into theslot 50. In order to accomplish this, the pin 40 has a diameter slightlygreater than the width of the slot 50. In the case of a pin having anominal diameter of A", the width of the slot will have a dimension ofthe order of a .003 less than the diameter of the pin. Because of thisinterference fit, a substantial force is employed to press the pin intothe slot. This force may be of the order of approximately one-half ton.

Once the pin 40 has been pressed into the bottom of the slot 50, and ofcourse the rocker arm 16 is in place at this time, the remainder of thefinal assembly operation is performed.

A peening tool 60 is pressed down against lips 54 with sufficientpressure to cause the metal to flow around the upper surface of the pin40 to the configuration shown in FIGURE 5. It is not necessary that theentire length of the lip 54 be peened, but a substantial amount of thelip should be peened down in order to retain the pin against outsideforces. Usually at least 50% of the length of the lip 54 will be peenedin this manner. It has been found convenient to perform the peeningoperation as a steady force rather than as a hammer blow. When analuminum die casting is used as the body portion of the pump, and thepin installed as described, pin 40 is held in place so securely that aforce of greater than one-half ton is required to pull the pin out ofthe slot. This again is based on the use of a pin of approximately A" indiameter. Larger pins or smaller pins will have corresponding greater orlesser withdrawal forces.

The shape of the slot or groove 50 can be varied for example as shown inFIGURE 6 where the bottom of the slot is contoured to closely fit theouter diameter of pin 40. Instead of the tapered lip 54 a lip 54A ofsomewhat rectangular cross section can be utilized. It is important thatthere be enough metal in the lip to allow for a portion of it to flowaround at least a part of the upper surface of the pin.

While the slot 50 has been shown with raised portions or lip 54, 54A, itwill be appreciated that the lips could be omitted and a portion of thedie casting adjacent the slot peened downwardly to achieve substantiallythe same result. Also it will be appreciated that the lever pin is heldso that it cannot rotate as has been customary in the past. Any attemptto withdraw the pin will usually result in a tearing away of a portionof the body thus making 3 it impractical if not impossible to replacethe pin and/ or lever arm. I claim: 1. A method of securing a lever pinin a die cast pump body comprising the steps of: 5

(a) forming said body with an aperture therein and a pin receiving slottransverse said aperture (b) inserting a lever pin of greater diameterthan the width of said slot in said slot and producing an interferencefit therebetween, and (c) securing said pin in said slot by peening bycompression a substantial portion of the edges of said slot to causeflow of metal into said slot and partially over said pin whereby tosecure said pin in said slot. 2. The method of claim 1, wherein the saidslot is 1 formed with raised portions constituting the said edges.

3. The method of claim 1, in which the step of inserting the lever pinin the said slot includes the step of forcing the pin with sufficientforce to overcome an interference fit whereby to seat the said pinfirmly in the bottom of the slot.

4. A diaphragm pump having a die cast apertured lever arm body, a slotin said body transverse the said aperture, a lever pin in said slot, thewidth of the said slot 4 being slightly less than the diameter of saidpin and producing an interference fit therebetween, a rocker arm pivotedon said pin, and peened over portions of the edges of said slot, saidportions extending a substantial length of said slot thereby retainingsaid pin in said slot.

5. The pump of claim 4 in which the said edges of the slot constituteraised portions extending substantially the length of said slot.

6. The pump of claim 4 including a draft of approxi- 10 mately onedegree in the walls of said slot.

References Cited UNITED STATES PATENTS 1,742,770 1/1930 Kamrath 103l501,920,497 8/1933 Clark et al. 29-515 2,017,154 10/1935 Larkin 29-5251,296,402 3/1919 Kahn 29-5l5 3,141,417 7/1964 Norberg et al 103150 HENRYF. RADUAZO, Primary Examiner us. 01. X.R. 29 515, s25

